Torque reaction devices and arms are designed to be used with torque generating devices or tools to transfer the reaction torque from the device or tool to the designated reaction point and to protect the operator from said reaction torque; overall they prevent rotation of the tool about itself. Typical reaction devices of the prior art are mounted on a small spline-like portion of the torque generating device. As a result, unwanted stress from the side load generated are applied to the torque generating device, causing slight deformation of the torque generating device which leads to great wear and reduction in performance of the torque generating device.
In some prior art devices, there is a distance between a point acting as a pivot point of the reaction arm and the point of reaction where the reaction force is applied. In such cases, an unwanted moment occurs between the reaction arm and torque generating device, when in use. This unwanted moment often creates an angular misalignment between the reaction arm and the torque generating device, which may in turn cause side forces which may actually slightly deform a portion of the torque generating device. Additionally, the unwanted moment and side forces waste energy which fails to go into operating the torque generating device and instead cause significant wear on the device.
There is thus a need in the art for a reaction arm which prevents annular misalignment between the reaction arm and the torque generating device and which directs all the energy generated by the device to the work area requiring the torque.
U.S. Pat. No. 8,192,322 to Van Bogaert et al discloses a wind turbine drive which is formed of a rotor with a rotor shaft and of a transmission box with a planetary gear unit. The transmission box is provided with a reaction arm which transmits a reaction torque around the rotary shaft from the transmission box to the nacelle so as to prevent the transmission box from turning along with the rotor shaft. It appears that this reference discloses a reaction arm preventing rotation of a transmission gear. However the reaction arm does not surround a significant part of the gear box.
U.S. Pat. No. 8,646,589 to Janson et al discloses a transmission latching mechanism including a component of a transmission gear-set. Two non-rotating housing components which surround a large part of the gear box comprise a reaction component. However, it appears that the reaction device in this case does not comprise a reaction arm per se, and does not prevent annular misalignment between the gear box and the reaction component.
U.S. Patent Application Publication 2013/0324344 to Pohl et al discloses continuously variable transmission devices and systems, including a torque governor comprising two reaction arms. The reaction arms assist the torque governor in adjusting the transmission speed ratio to maintain a constant operating torque. However, two reaction arms are required for operation of the disclosed device, and neither of the reaction arms engages a large portion of the device.